package com.tingyuge.base.structrue.quene;


/**
 * @Created by xiaodao
 */
public class LinkedListQueue<E> implements Queue<E> {

    private Node head,  tail;
    private int size;





    public LinkedListQueue() {
        head = null;
        tail =null;
        size =0;
    }

    private class Node {
        public E e;
        public Node next;

        public Node(E e, Node next) {
            this.e = e;
            this.next = next;
        }

        public Node(E e) {
            this(e, null);
        }

        public Node() {
            this(null, null);
        }
    }



    @Override
    public int getSize() {
        return size;
    }

    @Override
    public boolean isEmpty() {
        return size == 0;
    }

    @Override
    public void enQueue(E e) {
        if(tail == null){
            tail=new Node(e);
             head = tail;
        }else{
            tail.next = new Node(e);
            tail = tail.next;
        }
        size++;
    }

    @Override
    public E deQueue() {
       if(isEmpty()){
           throw  new IllegalArgumentException("queue is emtpy");
       }else{
            Node resNode= head;
            head=head.next;
            resNode.next=null;
            if(head==null){
                tail = null;

            }
            size--;
            return resNode.e;
       }
    }

    @Override
    public E getFront() {
         if(isEmpty()) new IllegalArgumentException("queue is emtpy");
        return head.e;
    }

    @Override
    public String toString() {

        StringBuilder res =new StringBuilder();
        res.append("queue: top  ");
        Node cur = head;
        while (cur!=null){
            res.append(cur.e+"->");
            cur = cur.next;
        }
       return res.append(" tail").toString();
    }

    public static void main(String[] args) {

    LinkedListQueue<Integer> linkedListQueue = new LinkedListQueue<>();

        for (int i = 0; i <5 ; i++) {
            linkedListQueue.enQueue(i);
            
        }

        System.out.println(linkedListQueue.toString());

        System.out.println(linkedListQueue.deQueue());
        System.out.println(linkedListQueue.toString());
        System.out.println(linkedListQueue.deQueue());
        System.out.println(linkedListQueue.toString());


    }
}
